Paper feeding apparatus and image forming system

ABSTRACT

A paper feeding apparatus for feeding paper from a paper-mounting table on which a paper bundle is mounted includes a suctioning conveyor that suctions and conveys uppermost paper among the paper bundle mounted on the paper-mounting table; and a hardware processor that controls the suctioning conveyor, wherein the suctioning conveyor includes a suction region for suctioning paper in a paper width direction orthogonal to a paper conveyance direction, and the hardware processor controls distribution of a suction amount in the paper width direction based on stiffness and a paper width, which is a paper size in the paper width direction, of paper.

The entire disclosure of Japanese patent Application No. 2018-017012, filed on Feb. 2, 2018, is incorporated herein by reference in its entirety.

BACKGROUND Technological Field

The present invention relates to a paper feeding apparatus and an image forming system.

Description of the Related Art

An image forming system for performing a series of various pieces of processing including image formation has recently been known. The image forming system includes one or more apparatuses arranged in series according to specifications required by a user. In addition to an image forming apparatus for the image formation, an apparatus constituting the image forming system includes a paper feeding apparatus (large-capacity paper feeding apparatus) that holds paper in a large amount, and feeds the paper to the image forming apparatus.

The paper feeding apparatus includes a paper feeding unit for feeding paper. The paper fed from the paper feeding unit is conveyed along the conveyance path, and discharged to the outside of the machine. The paper is then fed to an apparatus connected to the paper feeding apparatus on a downstream side, for example, the image forming apparatus. The paper feeding apparatus includes a paper-mounting table, and a paper bundle containing a plurality of pieces of paper is mounted on the paper-mounting table. The paper feeding unit feeds the uppermost paper among the paper bundle mounted on the paper-mounting table one by one. A unit that suctions and conveys paper is known as the type of paper feeding unit.

For example, JP H6-107347 A, JP 2006-327778 A, and JP H6-255815 A disclose methods for improving performance for separating the uppermost paper and the second and subsequent paper. JP H6-107347 A, JP 2006-327778 A, and JP H6-255815 A disclose contents for bending paper (the uppermost paper) that has been suctioned by providing a suctioning conveyor, which suctions and conveys the paper, with an uneven shape. According to the methods, a gap is formed between the uppermost paper and the second paper, and separation wind is introduced into the gap so that the paper can be successfully separated.

In addition, for example JP H6-144617 A and JP 2010-241590 A disclose methods of changing a suction region according to a paper width, which is a paper size in a paper width direction.

Unfortunately, in the methods disclosed in JP H6-144617 A and JP 2010-241590 A, paper is suctioned in a wide range in a paper width direction, so that the paper is planarly attached. This prevents a gap from being easily formed between the uppermost paper and the second paper, and there arises a problem that paper cannot successfully separated. The stiffness of paper also affects the problem.

In addition, the methods that use the uneven shape of the suctioning conveyor as disclosed in JP H6-107347 A, JP 2006-327778 A, and JP H6-255815 A need a large uneven shape for bending paper, so that the uneven shape may cause deformation of the paper. When paper is deformed, the paper may be wrinkled in a conveyance process, or deviation may occur in conveyance of the paper since the position of the paper is not appropriately regulated. In addition, the shape of a guide member for guiding the conveyance of paper needs to be designed in consideration of the deformation or the paper. In the case, for example, paper or thin paper that is curled cannot enter the guide member, and whereby conveyance failure may occur.

SUMMARY

The invention has been made in view of such circumstances, and an object of the invention is to provide a paper feeding apparatus and an image forming system capable of successfully separating paper during suction and conveyance of the paper.

To achieve the abovementioned object, according to an aspect of the present invention, there is provided a paper feeding apparatus for feeding paper from a paper-mounting table on which a paper bundle is mounted, and the paper feeding apparatus reflecting one aspect of the present invention comprises: a suctioning conveyor that suctions and conveys uppermost paper among the paper bundle mounted on the paper-mounting table; and a hardware processor that controls the suctioning conveyor, wherein the suctioning conveyor includes a suction region for suctioning paper in a paper width direction orthogonal to a paper conveyance direction, and the hardware processor controls distribution of a suction amount in the paper width direction based on stiffness and a paper width, which is a paper size in the paper width direction, of paper.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages and features provided by one or more embodiments of the invention will become more fully understood from the detailed description given hereinbelow and the appended drawings which are given by way of illustration only, and thus are not intended as a definition of the limits of the present invention:

FIG. 1 is a front view schematically illustrating the configuration of an image forming system according to a first embodiment;

FIG. 2 is a front view schematically illustrating the configuration of a paper feeding unit;

FIG. 3 is a top view schematically illustrating the configuration of a suctioning conveyor;

FIG. 4 is an explanatory view schematically illustrating the configuration of the suctioning conveyor;

FIG. 5 is a flowchart illustrating a paper feeding procedure with the paper feeding unit according to the first embodiment;

FIGS. 6A to 6C are explanatory views illustrating the relation between first and second suction regions and openings;

FIG. 7 is an explanatory view schematically illustrating the configuration of the suctioning conveyor according to a second embodiment;

FIG. 8 is a flowchart illustrating a paper feeding procedure with the paper feeding unit according to the second embodiment;

FIGS. 9A to 9C are explanatory views illustrating the relation between the first and second suction regions and the openings;

FIGS. 10A to 10C are explanatory views illustrating the relation between the first and second suction regions and the openings;

FIG. 11 is an explanatory view schematically illustrating a variation of the suctioning conveyor; and

FIGS. 12A to 12C are explanatory views illustrating variations of the suctioning conveyor.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, one or more embodiments of the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the disclosed embodiments.

First Embodiment

FIG. 1 is a front view schematically illustrating the configuration of to image forming system according to the present embodiment. The image forming system performs predetermined processing including image formation on paper P conveyed on a conveyance path, and includes a plurality of apparatuses arranged in series. The image forming system of the embodiment includes an image forming apparatus 100 and a large-capacity paper feeding apparatus 200. These apparatuses are arranged in the order of the large-capacity paper feeding apparatus 200 and the image forming apparatus 100 from the upstream side to the downstream side in a paper conveyance direction.

The image forming apparatus 100 forms an image on the paper P fed from the large-capacity paper feeding apparatus 200 or the paper P which the image forming apparatus 100 itself contains. The image forming apparatus 100 is, for example, an electrophotographic image forming apparatus, and is a so-called tandem type color image forming apparatus, which forms a full-color image, with a plurality of photoreceptors longitudinally arranged facing a single intermediate transfer belt. The image forming apparatus 100 mainly includes a script reading device SC, image formers 10Y, 10M, 10C, and 10K of four sets, a fixing device 40, and a controller 50. These elements are housed in a single housing.

The script reading device SC scans and exposes a script with an exposure device, and reads the reflected light with a line image sensor, thereby obtaining an image signal. The image signal is subjected to processing such as A/D conversion, shading correction, and compression, and then input to the controller 50 as image data. Note that the image data input to the controller 50 is not limited to that read by the script reading device SC. For example, the image data may be received from a personal computer connected to the image forming apparatus 100 or another image forming apparatus, or may be read from a portable recording medium such as a semiconductor memory.

The image formers 10Y, 10M, 10C, and 10K of four sets include the image former 10Y, the image former 10M, the image former 10C, and the image former 10K. The image former 10Y forms an image of yellow (Y). The image former 10M forms an image of magenta (M). The image former 10C forms an image of cyan (C). The image former 10K forms an image of black (K).

The image former 10Y includes a photoreceptor drum 11Y, an electrifier, an optical writer, a developing device, and a drum cleaner. The electrifier, the optical writer, the developing device, and the drum cleaner are placed around the photoreceptor drum 11Y. The surface of the photoreceptor drum 11Y is uniformly electrified by the electrifier, and a latent image is formed on the photoreceptor drum 11Y by scanning and exposing with the optical writer. The developing device develops the latent image on the photoreceptor drum 11Y by performing developing with toner. As a result, an image (toner image) corresponding to yellow is formed on the photoreceptor drum 11Y. The image formed on the photoreceptor drum 11Y is sequentially transferred to a predetermined position on an intermediate transfer belt 15, which is an endless belt, by a primary transfer roller.

The remaining image formers 10M, 10C, and 10K include photoreceptor drums 11M, 11C, and 11K, respectively, and include electrifiers, optical writers, developing devices and drum cleaners. The electrifiers, the optical writers, the developing devices and the drum cleaners are placed around the photoreceptor drums 11M, 11C, and 11K. Details thereof are similar to that of the image former 10Y.

The image transferred onto the intermediate transfer belt 15 is transferred by a secondary transfer roller 16 to the paper P which is conveyed by a paper conveyor 20 at predetermined timing. The secondary transfer roller 16 is placed in pressure contact with the intermediate transfer belt 15, and a transfer nip is formed between secondary transfer roller 16 and the intermediate transfer belt 15.

The paper conveyor 20 conveys the paper P fed by a paper feeding roller 22 from a paper tray 21 or the paper P fed from the large-capacity paper feeding apparatus 200 along the conveyance path. The paper conveyor 20 includes a conveyance roller and a conveyance guide. A paper discharging roller 23 and a switching gate 24, which will be described later, also constitute a part of the paper conveyor 20.

The fixing device 40 applies fixing processing to the paper P onto which the image has been transferred. The fixing device 40 includes, for example, a pair of fixing rollers and a heater. The fixing rollers are brought into pressure contact with each other to form a fixing nip. The heater heats one of the fixing rollers. While the paper P passes through the fixing nip, the fixing device 40 fixes the transferred image onto the paper P by pressurization with the pair of fixing rollers and heat of the fixing roller. The paper discharging roller 23 discharges the paper P that has been subjected to the fixing processing to the outside of the machine.

When an image is formed on the back of the paper P, the paper P, on whose front surface the image has already been formed, is conveyed to a paper refeeding conveyance path by the switching gate 24. In the paper refeeding conveyance path, the rear end of the conveyed paper P is pinched by a reversing roller to be inverted, whereby the front and back of the paper P are reversed. The paper P, whose front and back are reversed, is conveyed by a plurality of conveyance rollers, and joins the conveyance path on the more upstream side than the position of the secondary transfer roller 16 in order to form an image on the back of the paper.

The controller 50 controls operation of the image forming apparatus 100. A microcomputer mainly including a CPU, a ROM, a RAM, and an I/O interface can be used as the controller 50. The CPU (is a processor that) controls the operation of the image forming apparatus 100 by executing various programs. The ROM stores the various programs to be executed by the CPU in the form of CPU-readable program codes. The ROM also stores data necessary for executing the programs. The RAM is a memory serving as a work storage area. When read by the CPU, the programs and data stored in the ROM are developed on the RAM. The CPU then performs various pieces of processing based on the programs and data developed on the RAM.

An operation panel 60 is an input part through which desired information can be input according to information displayed on a display. Systems such as a touch panel system can be adopted for the operation panel 60. Users can set contents (e.g., information on the paper P (e.g., paper size and type), and density and magnification of an image) of a job through operations on the operation panel 60. The controller 50 acquires the set information. The operation panel 60 also functions as a display part that displays various pieces of information to the user by being controlled by the controller 50.

The large-capacity paper feeding apparatus 200 feeds the paper P. The large-capacity paper feeding apparatus 200 includes one or more paper feeding units 210 and a controller 250. One or more paper feeding units 210 includes, for example, three paper feeding units 210 placed in upper, middle, and lower stages. These elements are housed in a single housing.

FIG. 2 is a front view schematically illustrating the configuration of the paper feeding unit 210. The paper feeding unit 210 houses a plurality of pieces of paper P (paper bundle), and feeds the uppermost paper P in the housed paper bundle to the conveyance path. The paper feeding unit 210 mainly includes a paper-mounting table 211, a leading-end regulating member 212, a rear-end regulating member 213, a suctioning conveyor 220, a leading-end blower 230, and side-end blowers 240.

In the paper feeding unit 210, the paper bundle is mounted on the paper-mounting table 211. The paper-mounting table 211 is provided with an electric lifting mechanism, and configured to be liftable along the vertical direction. The paper-mounting table 211 is also provided with a guide rail 214, and configured so as to be drawn from the large-capacity paper feeding apparatus 200.

The leading-end regulating member 212 regulates the leading end of the paper bundle on the paper-mounting table 211. The leading-end regulating member 212 is fixed to the main body of the large-capacity paper feeding apparatus 200.

The rear-end regulating member 213 regulates the rear end of the paper bundle on the paper-mounting table 211. The rear-end regulating member 213 is configured to be movable along the paper conveyance direction, and the position thereof is adjusted according to the paper size in the paper conveyance direction.

A height sensor (not illustrated) for detecting the height of the paper bundle mounted on the paper-mounting table 211 is placed on the rear-end regulating member 213. The controller 250 drives the lifting mechanism based on a signal from the height sensor, and controls rise and fall of the paper-mounting table 211. The uppermost paper P of the paper bundle placed on the paper-mounting table 211 is maintained at a constant height under the control.

The suctioning conveyor 220 is placed above the paper-mounting table 211 (paper P) while facing the paper-mounting table 211. The suctioning conveyor 220 suctions and conveys the uppermost paper P among the paper bundle mounted on the paper-mounting table 211.

The suctioning conveyor 220 mainly includes a conveyor 211 and a suctioner 226. Here, FIG. 3 is a top view schematically illustrating the configuration of the suctioning conveyor 220. FIG. 4 is an explanatory view schematically illustrating the configuration of the suctioning conveyor 220.

The conveyor 221 has a function of conveying the paper P, and includes an endless belt member. In the embodiment, the conveyor 221 includes five belt members 221 a to 221 e that are arranged adjacently in a paper width direction orthogonal to the paper conveyance direction, and the individual belt members 221 a to 221 e are placed along the paper conveyance direction.

The individual belt members 221 a to 221 e are wound around large-diameter driving rollers 223 a to 223 e and two driven rollers 224 a to 224 e and 225 a to 225 e. The large-diameter driving rollers 223 a to 223 e are connected to a driving source. The driving rollers 223 a to 223 e are placed on the upstream side in the paper conveyance direction, and the two driven rollers 224 a to 224 e and 225 a to 225 e are placed separately in the vertical direction on the downstream side in the paper conveyance direction.

The individual belt members 221 a to 221 e are rotated by rotational drive of the driving rollers 223 a to 223 e, and suction surfaces (belt regions on the lower side) facing the paper P move in the paper conveyance direction. Each of the driving rollers 223 a to 223 e is rotationally driven in synchronization with each other, and the individual belt members 221 a to 221 e are also synchronously rotated. A plurality of small-diameter through holes (not illustrated) is provided in the individual belt members 221 a to 221 e.

The suctioner 226 has a function of suctioning the uppermost paper P and attaching the uppermost paper P to the belt members 221 a to 221 e. The suctioner 226 is placed inside the belt members 221 a to 221 e, which are the conveyor 221, and faces the paper-mounting table 211 (paper P) across the belt members 221 a to 221 e (suction surfaces).

The suctioner 226 mainly includes a suction fan 227 and a duct 228.

The suction fen 227 suctions air.

The suction fan 227 is connected to the duct 228, and the duct 228 guides the air to the suction can 227. The duct 228 is placed inside the belt members 221 a to 221 e so as to cross the individual belt members 221 a to 221 e. Five openings 228 a to 228 e are provided on the lower surface of the duct 228, that is, the surface facing the paper-mounting table 211 (paper P) across the belt members 221 a to 221 e. The five openings 228 a to 228 e are provided adjacently in the paper width direction so as to correspond to the five belt members 221 a to 221 e. A plurality of internal channels corresponding to the individual openings 228 a to 228 e is also provided inside the duct 228. Valves 229 a to 229 e for blocking the communication between a common channel and the internal channel of the duct 228 are provided in the individual internal channels. The suction fan 227 is connected to the common channel.

In the suctioning conveyor 220 having such a configuration, air is drawn into the duct 228 through the individual openings 228 a to 228 e by operation of the suction fan 227. As a result, the individual openings 228 a to 228 e function as suction regions for suctioning the paper P. Meanwhile, when the valves 229 a to 229 e are set in the closed state, the internal channels communicating with the openings 228 a to 228 e are blocked. In the case, suction through the openings 228 a to 228 e is not performed. Consequently, the distribution of a suction amount in the paper width direction can be controlled by individually setting opening and closing of the valves 229 a to 229 e.

FIGS. 1 and 2 will be referred again. The leading-end blower 230 is placed on the leading-end side of the paper bundle and near the suctioning conveyor 220. The leading-end blower 230 has a function of separating the uppermost paper P from the second and subsequent pieces of paper P by blowing the paper bundle mounted on the paper-mounting table 211 from the leading-end side of the paper. The leading-end blower 230 mainly includes a blowing machine 231 and a blowing port 232.

The blowing machine 231 is, for example, a multiblade fan (sirocco fan). The blowing port 232 is a part for blowing wind output from the blowing machine 231 toward the upper part of the paper bundle.

Each of the side-end blowers 240 is placed on each of the lateral sides of the paper-mounting table 211. The side-end blower 240 has a function of floating the uppermost paper P by blowing the paper bundle mounted on the paper-mounting table 211 on the side end parallel with the paper conveyance direction. In the embodiment, a pair of side-end blowers 240 are prepared, and these side-end blowers 240 are placed so as to face each other across the paper bundle. The individual side-end blowers 240 have the same structure as the leading-end blower 230, and mainly include a blowing machine 241 and a blowing port 242.

The blowing machine 241 is, for example, a multiblade fan (sirocco fan). The blowing port 242 is a part for blowing wind output from the blowing machine 241 toward the upper part of the paper bundle.

The controller 250 controls operation of the large-capacity paper feeding apparatus 200. A microcomputer mainly including a CPU, a ROM, a RAM, and an I/O interface can be used as the controller 250. The CPU (is a processor that) controls the operation of the large-capacity paper feeding apparatus 200 by executing various programs. The ROM stores the various programs to be executed by the CPU in the form of CPU-readable program codes. The ROM also stores data necessary for executing the programs. The RAM is a memory serving as a work storage area. When read by the CPU, the programs and data stored in the ROM are developed on the RAM. The CPU then performs various pieces of processing based on the programs and data developed on the RAM.

The controller 250 controls the suctioning conveyor 220, the leading-end blower 230, and the side-end blower 240 to suction and convey the uppermost paper P among the paper bundle mounted on the paper-mounting table 211. In relation to the embodiment, the controller 250 controls the distribution of the suction amount in the paper width direction based on the stiffness and the paper width, which corresponds to the paper size in the paper width direction, of the paper P.

Detection signals from various sensors are input to the controller 250. A paper attachment sensor 251 detects attachment of the paper P onto the suctioning conveyor 220 (conveyor 221) (see. FIG. 3). In addition, the paper detection sensor 252 is placed near a conveyance roller 201 at which the paper P delivered from the paper feeding unit 210 first arrives, and detects that the leading end of the paper P arrives at a conveyance roller 201 (See FIG. 1). In addition, the controller 250 can communicate with the controller 50 of the image forming apparatus 100.

The operation of the large capacity paper feeding apparatus 200 according to the embodiment will now be described. Here, FIG. 5 is a flowchart illustrating a paper feeding procedure with the paper feeding unit 210. Triggered by, for example, paper feeding start information input from the image forming apparatus 100, the processing illustrated in the flowchart is executed by the controller 250. Note that, in the following description, unless otherwise specified, the terms “center of paper” and “both ends of paper” are used to mean the center of paper and both ends of paper in the paper width direction. In addition, the center of paper and both ends of paper relatively indicate regions in the paper, and do not absolutely indicate only a specific region of the paper P.

First, in Step S1, the controller 250 acquires information on the paper P to be fed. In relation to the embodiment, the stiffness and paper width of the paper P correspond to the information. For example, the image forming apparatus 100 holds the information on the paper P housed in the paper feeding unit 210, and the controller 250 acquires the information on the paper P from the image forming apparatus 100. Note that, the large capacity paper feeding apparatus 200 itself may hold the information on the paper P housed in each of the paper feeding units 210.

In Step S2, the controller 250 sets the distribution of a suction amount with the suctioning conveyor 220 based on the stiffness and paper width of the paper P. In general, the suction amount in the paper width direction is uniformly set. In contrast, in the embodiment, the distribution of the suction amount in the paper width direction is controlled based on the stiffness and paper width of the paper P.

FIGS. 6A to 6C are explanatory views illustrating the relation between first and second suction regions R1 and R2 and the openings 228 a to 228 e. In the control according to the embodiment, suction is performed in the first suction region R1 corresponding to the center of paper, and the suction is not performed in the second suction region R2 corresponding to both ends of the paper. The distribution of the suction amount is controlled in the setting modes of the first and second suction regions R1 and R2.

Specifically, a central opening 228 c is set as the first suction region R1. In contrast, two openings 228 b and 228 d and two openings 228 a and 228 e are set as the first or second suction region R1 or R2 according to the stiffness and paper width of the paper P. The openings 228 b and 228 d are positioned on both sides of the central opening 228 c. The openings 228 a and 228 e are positioned at the outermost ends. In this case, the valves 229 a to 229 e in the openings 228 a to 228 e that correspond to the first suction region R1 are set in an open state, and the valves 229 a to 229 e in the openings 228 a to 228 e that correspond to the second suction region R2 are set in a closed state.

The paper P having a small paper width is first illustrated in FIG. 6A. The central opening 228 c is set as the first suction region R1. In contrast, the remaining openings 228 a, 228 b, 228 d, and 228 e are set as the second suction region R2. That is, in the distribution of the suction amount, the central opening 228 c is in a suction state, and the remaining openings 228 a, 228 b, 228 d, and 228 e are in a non-suction state.

The paper P having a large paper width is also illustrated in FIG. 6B. The central opening 228 c and the two openings 228 b and 228 d adjacent to the central opening 228 c are set as the first suction region R1. In contrast, the two openings 228 a and 228 e positioned at the outermost ends are set as the second suction region R2. That is, in the distribution of the suction amount, the central opening 228 c and the two openings 228 b and 228 d adjacent to the central opening 228 c are in the suction state, and the remaining openings 228 a and 228 e are in the non-suction state.

As described above, in any paper width, suction is performed in the first suction region R1 corresponding to the center of paper, and the suction is not performed in the second suction region R2 corresponding to both ends of the paper. Consequently, when the paper P is attached onto the suctioning conveyor 220, the suction is not performed in the second suction region R2, so that both ends of the paper sag. The sagging of both ends of the paper forms a gap between the uppermost paper P and the second paper P, and separation wind from the leading-end blower 230 can be sent between the uppermost paper P and the second paper P. As a result, the paper P can be successfully separated.

In addition, for the paper P having a large paper width, two openings 228 b and 228 d positioned on both sides of the central opening 228 c are also set as the first suction region R1. That is, for the paper P having a large paper width, the range of the first suction region R1 is expanded to the paper-end sides as compared with the paper P having a small paper width. The larger the paper width is, the more significantly both ends of the paper sag due to the influence of the own weight of the paper. The expansion of the range of the first suction region R1 and the reduction of the range of the second suction region R2, however, can inhibit the extreme sagging of both ends of the paper. As a result, the interference of the paper P with a guide member during the feeding of the paper P is inhibited, and the paper P can be appropriately fed.

In addition, even for the same paper width, the first and second suction regions R1 and R2 are differently set depending on the stiffness. Here, an example of paper P having a small paper width will be described.

The paper P having a large stiffness is first illustrated in FIG. 6A just as the paper P having a small paper width. The central opening 228 c is set as the first suction region R1. In contrast, the remaining openings 228 a, 228 b, 228 d, and 228 e are set as the second suction region R2. That is, in the distribution of the suction amount, the central opening 228 c is in a suction state, and the remaining openings 228 a, 228 b, 228 d, and 228 e are in a non-suction state.

Meanwhile, the paper P having a small stiffness is illustrated in FIG. 6C. The central opening 228 c and the two openings 228 b and 228 d adjacent to the central opening 228 c are set as the first suction region R1. In contrast, the two openings 228 a and 228 e positioned at the outermost ends are set as the second suction region R2. That is, in the distribution of the suction amount, the central opening 228 c and the two openings 228 b and 228 d adjacent to the central opening 228 c are in the suction state, and the remaining openings 228 a and 228 e are in the non-suction state.

As described above, in any stiffness, suction is performed in the first suction region R1 corresponding to the center of paper, and the suction is not performed in the second suction region R2 corresponding to both ends of the paper. Consequently, when the paper P is attached onto the suctioning conveyor 220, the suction is not performed in the second suction region R2, so that both ends of the paper sag. The sagging of both ends of the paper forms a gap between the uppermost paper P and the second paper P, and separation wind from the leading-end blower 230 can be sent between the uppermost paper P and the second paper P. As a result, the paper P can be successfully separated.

In addition, for the paper P having a small stiffness, two openings 228 b and 228 d positioned on both sides of the central opening 228 c are also set as the first suction region R1. That is, for the paper P having a small stiffness, the range of first suction region R1 is expanded to the paper-end sides as compared with the paper P having a large stiffness. The smaller the stiffness is, the more significantly both ends of the paper sag due to the reduced firmness of the paper P. The expansion of the range of the first suction region R1 and the reduction of the range of the second suction region R2, however, can inhibit the extreme sagging of both ends of the paper. As a result, the interference of the paper P with as guide member during the feeding of the paper P is inhibited, and the paper P can be appropriately fed.

In Step S3, the controller 250 starts suction with the suctioner 226, and starts the blowing with the side-end blower 240. The suction with the suctioner 226 is executed according to the first and second suction regions R1 and R2 set in Step S2. The blowing with the side-end blower 240 and the suction with the suctioner 226 cause the uppermost paper P among the paper bundle mounted on the paper-mounting table 211 to float against the own weight of the paper P.

In Step S4, the controller 250 determines whether or not the uppermost paper P has been attached onto the conveyor 221. The controller 250 makes the determination with reference to the paper attachment sensor 251. When the uppermost paper P is attached onto the conveyor 221, the controller 250 makes a positive determination in Step S4, and the operation proceeds to Step S5. In contrast, when the uppermost paper P is not attached onto the conveyor 221, the controller 250 makes a negative determination in Step S4, and the operation returns to Step S4.

In Step S5, the controller 250 starts the blowing with the leading-end blower 230. The air blown from the leading-end blower 230 causes wind (separation wind) to flow between the uppermost paper P and the paper P (second uppermost paper P) under the uppermost paper P. As a result, even when the second paper P follows the uppermost paper P attached onto the conveyor 221, the second paper P is separated from the uppermost paper P.

In Step S6, the controller 250 starts the driving of the conveyor 221, and starts the conveyance of the paper P. Specifically, the controller 250 rotationally drives the belt members 221 a to 221 e of the conveyor 221. As a result, the uppermost paper P attached onto the suctioning conveyor 220 is delivered to the conveyance path.

In Step S7, the controller 250 determines whether or not the paper P has arrived at the conveyance roller 201. The controller 250 makes the determination with reference to the paper detection sensor 252. When the paper P has arrived at the conveyance roller 201, the controller 250 makes a positive determination in Step S7, and the operation proceeds to Step S8. In contrast, when the paper P has not arrived at the conveyance roller 201, the controller 250 makes a negative determination in Step S7, and the operation returns to Step S7.

In Step S8, the controller 250 stops the driving of the conveyor 221, and slops the blowing with the leading-end blower 230.

In Step S9, the controller 250 determines whether or not the next paper P to be conveyed exists. When the next paper P exists, the controller 250 makes as positive determination in Step S9, and the operation returns to Step S4. In contrast, when the next paper P does not exist, the controller 250 makes a negative determination in Step S9, and finishes the routine.

As described above, the large-capacity paper feeding apparatus 200 according to the embodiment includes the suctioning conveyor 220 and the controller 250. The suctioning conveyor 220 suctions and conveys the paper P mounted on the paper-amounting table 211. The controller 250 controls the suctioning conveyor 220. Here, the suctioning conveyor 220 has a suction region for suctioning the paper P the paper width direction. The controller 250 then controls the distribution of the suction amount in the paper width direction based on the stiffness and paper width of the paper P.

According to the configuration, the suction amount can be set for each region in the paper P by controlling the distribution of the suction amount in the paper width direction. This enables control of the shape of the paper P to be attached onto the suctioning conveyor 220. As a result, a gap can be secured between the uppermost paper P and the second paper P, and the paper P can be successfully separated.

In addition, in the embodiment, the controller 250 performs suction in the first suction region R1 corresponding to the center of paper, and does not perform the suction in the second suction region R2 corresponding to both ends of the paper.

According to the configuration, when the paper P is attached onto the suctioning conveyor 220, the suction is not performed in the second suction region R2, so that both ends of the paper sag. The sagging of both ends of the paper can form a gap on the center in the paper width direction and between the uppermost paper P and the second paper P. In such a configuration, separation wind from the leading-end blower 230 can be sent between the uppermost paper P and the second paper P, so that the paper P can be successfully separated.

Note that, in the embodiment, a method in which suction is not performed in the second suction region R2 is described. The controller 250, however, my control the distribution of the suction amount in the paper width direction such that the suction amount in the second suction region R2 is smaller than that in the first suction region R1. Even in such a configuration, the suction amount at both ends of the paper is reduced, so that the effect of sagging of both ends of the paper can be obtained.

Note that, in the embodiment, a method of controlling the distribution of the suction amount in the paper width direction based on the stiffness and paper width of the paper P is described. In the large-capacity paper feeding apparatus 200 according to the embodiment, however, the control may be performed based on at least one of the stiffness and paper width of the paper P as long as the distribution of the suction amount in the paper width direction is controlled such that the suction amount in the second suction region R2 i smaller than that in the first suction region R1.

Furthermore, in the embodiment, the smaller stiffness the paper P has, the more the controller 250 expands the range of the first suction region R1 toward both end sides of the paper.

The smaller the stiffness is, the more significantly both ends of the paper sag due to the reduced firmness of the paper P. The expansion of the range of the first suction region R1, however, can inhibit the excess sagging of both ends of the paper. As a result, the interference of the paper P with a guide member during the feeding of the paper P is inhibited, and the paper P can be appropriately fed.

Furthermore, in the embodiment, the larger the paper width is, the more the controller 250 expands the range of the first suction region R1 toward both end sides of the paper.

The larger the paper width is, the more significantly both ends of the paper sag due to the influence of the own weight of the paper. The expansion of the range of the first suction region R1, however, can inhibit the excess sagging of both ends of the paper. As a result, the interference of the paper P with a guide member during the feeding of the paper P is inhibited, and the paper P can be appropriately fed.

Second Embodiment

An image forming system according to the second embodiment will now be described. The difference between the image forming system according to the embodiment and that in the first embodiment is in that blowing to the paper P is performed in the second suction region R2. Descriptions of the content overlapping with the content of the first embodiment will be omitted, and the differences will be mainly described below.

FIG. 7 is an explanatory view schematically illustrating the configuration of the suctioning conveyor 220 according to the second embodiment. In the embodiment, the suctioning conveyor 220 is provided with a blowing machine 260 for blowing the paper P. For example, a multiblade fan (sirocco fan) can be used for the blowing machine 260. The blowing machine 260 is connected to the duct 228 with a necessary structure, and communicates with individual internal channels communicating with the five openings 228 a to 228 e. Air delivered from the blowing machine 260 is blown from the openings 228 a to 228 e through the duct 228 by the driving of the blowing machine 260. This configuration enables blowing to the paper P. The blowing to the paper P is an air flow in the direction opposite to that of suction of the paper P, and corresponds to the suction, which is defined in a minus direction (opposite direction). In other words, a blowing amount corresponds to the suction amount defined in minus.

In addition, valves (not illustrated) are provided in a communication part between the individual internal channels and the blowing machine 260. When the valves are set in a closed state, the internal channels communicating with the openings 228 a to 228 e are blocked. In the case, blowing from the openings 228 a to 228 e is not performed.

As one of the features of the embodiment, the controller 250 suctions paper P in be first suction region R1, and blows the paper P in the second suction region R2.

The operation of the large-capacity paper feeding apparatus 200 according to the embodiment will now be described. Here, FIG. 8 is a flowchart illustrating the paper feeding procedure with the paper feeding unit 210. Triggered by, for example, paper feeding start information input from the image forming apparatus 100, the processing illustrated in the flowchart is executed by the controller 250. Note that, since each of the pieces of processing in Steps S21, S23, S24, S26 to S28, and S30 corresponds to each of the pieces of processing in Steps S1, S3 to S7, and S9 described in the first embodiment, detailed descriptions thereof will be omitted.

In Step S22, the controller 250 sets the distribution of a suction amount with the suctioning conveyor 220 based on the stiffness and paper width of the paper P. In general, the suctioning conveyor 220 performs suction in the entire region in the paper width direction. In contrast, in the embodiment, the distribution of the suction amount in the paper width direction is controlled based on the stiffness and paper width of the paper P.

FIGS. 9A to 9C are explanatory views illustrating the relation between the first and second suction regions R1 and R2 and the openings 228 a to 228 e. In the control according to the embodiment, suction is performed in the first suction region R1 corresponding to the center of paper in the paper width direction, and the blowing to the paper P is performed in the second suction region R2 corresponding to both ends of the paper. The distribution of the suction amount is adjusted in the setting modes of the first and second suction regions R1 and R2.

Specifically, the central opening 228 c is set as the first suction region R1. In contrast, the two openings 228 b and 228 d and the two openings 228 a and 228 e are set as the first or second suction region R1 or R2 according to the stiffness and paper width of the paper P. The openings 228 b and 228 d are positioned on both sides of the central opening 228 c. The openings 228 a and 228 e are positioned at the outermost ends. In this case, among the valves 229 a to 229 e for controlling the suction amount with the suction hill 227, a valve/valves corresponding to the first suction region R1 is/are set in the open state, and a valve/valves corresponding to the second suction region R2 is/are set in the closed state. In addition, among the valves for controlling the blowing amount with the blowing machine 260, a valve/valves corresponding to the first suction region R1 is/are set in the open state and a valve/valves corresponding to the second suction region R2 is/are set in the closed state.

The paper P having a small paper width is first illustrated in FIG. 9A. The central opening 228 c is set as the first suction region R1. In contrast, the remaining openings 228 a. 228 b. 228 d, and 228 e are set as the second suction region R2. That is, in the distribution of the suction amount, the central opening 228 c is in a suction state, and the remaining openings 228 a, 228 b, 228 d, and 228 e are in a blowing state.

The paper P having a large paper width is also illustrated in FIG. 9B. The central opening 228 c and the two openings 228 b and 228 d adjacent to the central opening 228 e are set as the first suction region R1. In contrast, the two openings 228 a and 228 e positioned at the outermost ends are set as the second suction region R2. That is, in the distribution of the suction amount, the central opening 228 c and the two openings 228 b and 228 d adjacent to the central opening 228 c are in the suction state, and the remaining openings 228 a and 228 e are in the blowing state.

As described above, even for the paper P having any paper width, suction is performed in the first suction region R1 corresponding to the center of paper, and the blowing is performed in the second suction region R2 corresponding to both ends of the paper. Consequently, when the paper P is attached on the suctioning conveyor 220, downward wind acts in the second suction region R2, so that both ends of the paper successfully sag. The sagging of both ends of the paper forms a gap between the uppermost paper P and the second paper P, and separation wind from the leading-end blower 230 can be sent between the uppermost paper P and the second paper P. As a result, the paper P can be successfully separated.

In addition, for the paper P having a large paper width, two openings 228 b and 228 d positioned on both sides of the central opening 228 c are also set as the first suction region R1. That is, for the paper P having a large paper width, the range of the first suction region R1 is expanded to the paper-end sides as compared with the paper P having a small paper width. The larger the paper width is, the more significantly both ends of the paper sag due to the influence of the own weight of the paper. The expansion of the range of the first suction region R1 and the reduction of the range of the second suction region R2, however, can inhibit the extreme sagging of both ends of the paper. As a result, the interference of the paper P with a guide member during the feeding of the paper P is inhibited, and the paper P can be appropriately fed.

In addition, even for the same paper width, the first and second suction regions R1 and R2 are differently set depending on the stiffness. Here, an example of the paper P having a small paper width will be described.

The paper P having a large stiffness is first illustrated in FIG. 9A just as the paper P having a small paper width. The central opening 228 c is set as the first suction region R1. In contrast, the remaining openings 228 a, 228 b, 228 d, and 228 e are set as the second suction region R2. That is, in the distribution of the suction amount, the central opening 228 c is in a suction state, and the remaining openings 228 a, 228 b, 228 d, and 228 e are in a blowing state.

Meanwhile, the paper P having a small stiffness is illustrated in FIG. 9C. The central opening 228 c and the two openings 228 b and 228 d adjacent to the central opening 228 c are set as the first suction region R1. In contrast, the two openings 228 a and 228 e positioned at the outermost ends are set as the second suction region R2. That is, in the distribution of the suction amount, the central opening 228 c and the two openings 228 b and 228 d adjacent to the central opening 228 c are in the suction state, and the remaining openings 228 a and 228 e are in the blowing state.

As described above, in any stiffness, suction is performed in the first suction region R1 corresponding to the center of paper, and the blowing is performed in the second suction region R2 corresponding to both ends of the paper. Consequently, when the paper P is attached onto the suctioning conveyor 220, downward wind acts in the second suction region R2, so that both ends of the paper successfully sag. The sagging of both ends of the paper forms a gap between the uppermost paper P and the second paper P, and separation wind from the leading-end blower 230 can be sent between the uppermost paper P and the second paper P. As a result, the paper P can be successfully separated.

In addition, for the paper P having a small stiffness, two openings 228 b and 228 d positioned on both sides of the central opening 228 c are also set as the first suction region R1. That is, for the paper P having a small stiffness, the range of the firm suction region R1 is expanded to the paper-end sides as compared with the paper P having a lame stiffness. The smaller the stiffness is, the more significantly both ends of the paper sag due to the reduced firmness of the paper P. The expansion of the range of the first suction region R1 and the reduction of the range of the second suction region R2, however, can inhibit the extreme sagging of both ends of the paper. As a result, the interference of the paper P with a guide member during the feeding of the paper P is inhibited, and the paper P can be appropriately fed.

In Step S25, the controller 250 starts the blowing with the blowing machine 260 of the suctioning conveyor 220. That is, the blowing machine 260 performs the blowing after the attachment of the paper P onto the conveyor 221 and before the start of the blowing with the leading-end blower 230.

In Step S29, the controller 250 stops the driving of the conveyor 221, and stops the blowing with the leading-end blower 230. The controller 250 also stops the blowing with the blowing machine 260.

As described above, in the large-capacity paper feeding apparatus 200 according to the embodiment, the blowing machine 260 for blowing the paper P is connected to the suctioning conveyor 220. The controller 250 then suctions the paper P in the first suction region R1, and blows the paper P in the second suction region R2.

In the configuration, downward wind acts in the second suction region R2 during the suction of the paper P, so that both ends of the paper successfully sag. The sagging of both ends of the paper forms a gap between the uppermost paper P and the second paper P, and separation wind from the leading-end blower 230 can be sent between the uppermost paper P and the second paper P. As a result, the paper P can be successfully separated.

Furthermore, in the embodiment, the controller 250 starts blowing the paper P in the second suction region R2 after the uppermost paper P mounted on the paper-mounting table 211 is attached onto the suctioning conveyor 220.

According to the configuration, the blowing in the direction opposite to that of the suction of the paper P is performed after the attachment of the paper. This configuration enables smooth suction of the paper P.

Furthermore, in the embodiment, the controller 250 starts blowing the paper P in the second suction region R2 before the leading-end blower 230 sends separation wind.

In the configuration, the leading-end blower 230 starts the blowing with a gap formed between the uppermost paper P and the second paper P, and separation wind can be appropriately sent between the uppermost paper P and the second paper P. This configuration enables the paper P to be successfully separated.

Note that, in the embodiment, the ranges of the first and second suction regions R1 and R2 are adjusted as the control of the suction amount distribution according to the stiffness of paper width of the paper P. The scale of the blowing amount, however, may be adjusted without changing the ranges of the first and second suction regions R1 and R2. For example, FIG. 10A illustrates the paper P having a small paper width. The larger the paper width is (FIG. 10B), the more the controller 250 decreases the blowing amount in the second suction region R2. In addition, FIG. 10A illustrates the paper P having a large stiffness. The smaller stiffness the paper P has (FIG. 10C), the more the controller 250 decreases the blowing amount in the second suction region R2.

Furthermore, in the embodiment, the blowing amount in the second suction region R2 is assumed to be equal in the paper conveyance direction. As illustrated in FIG. 11, however, the blowing amount in the second suction region R2 may be set such that the blowing amount on the rear-end side of the paper is smaller than that on the leading-end side of the paper. This configuration enables both ends of the paper to appropriately sag without the decreasing performance of suctioning the paper P.

Furthermore, in the embodiment, the suction surface of the suctioning conveyor 220 is set to have a shape of surface more flat than both end sides of the paper. The suctioning conveyor 220, however, may have a projecting shape such that a distance from the paper P to the suction surface on the center of the paper is larger than that on both end sides of the paper. For example, as illustrated in FIG. 12A, such a projecting shape can be obtained by changing the height at which the belt members 221 a to 221 e are placed in the paper width direction. In addition, a distance between belts of the belt members 221 a to 221 e may be changed in the paper width direction in another method, as illustrated in FIGS. 12B and 12C.

The configuration enables both ends of the paper to be bent by using the shape of the suctioning conveyor 220. To bend the paper P by using only the structure of the suctioning conveyor 220 without changing the distribution of the blowing amount, a large uneven shape is required to be set in the suctioning conveyor 220. Usage in combination with the above-described distribution control of the suction amount, however, eliminates the need of providing the large uneven shape in the suctioning conveyor 220. Consequently, the deformation of the paper P due to the uneven shape in the suctioning conveyor 220 can be inhibited.

Although the image forming system according to the embodiment of the invention has been described above, it is needless to say that the invention is not limited to the above-described embodiments, and various variations are possible within the scope of the invention. In addition to the image forming system, the paper feeding apparatus (large-capacity paper feeding apparatus) itself constituting the image forming system also functions as a part of the invention. Furthermore, the invention may be applied to a paper feeding unit built in an image forming apparatus, and in such a case, also the image forming apparatus can function as a part of the invention.

Furthermore, in the case where the image forming system includes the image forming apparatus and the paper feeding apparatus, the image forming apparatus and the paper feeding apparatus may each have a control function, or the image forming system may have a single control function in which the control functions are integrated. Both an individual control function and a single control function have a function as a controller for controlling the image forming apparatus and the paper feeding apparatus.

Furthermore, although, in the embodiment, the number of the belt members of the suctioning conveyor corresponds to that of the openings of the suctioning conveyor, the invention is not limited to the configuration. For example, a single common opening may be set for a plurality of belt members, or a plurality of openings may be set for a single belt member having a large lateral width, in the lateral width.

In addition, although a valve is used in a method of switching the distribution of the suction amount, any method can also be widely applied as long as the method can block the into channel.

Furthermore, although the first and second suction regions are set by opening and closing an opening, the first and second suction regions may be set by adjusting an opening width of the opening using an adjusting mechanism such as a shutter.

Although embodiments of the present invention have been described and illustrated in detail, the disclosed embodiments are made for purposes of illustration and example only and not limitation. The scope of the present invention should be interpreted by terms of the appended claims. 

What is claimed is:
 1. A paper feeding apparatus for feeding paper from a paper-mounting table on which a paper bundle is mounted, comprising; a suctioning conveyor that suctions and conveys uppermost paper among the paper bundle mounted on the paper-mounting table; and a hardware processor that controls the suctioning conveyor, wherein the suctioning conveyor includes a suction region for suctioning paper in a paper width direction orthogonal to a paper conveyance direction, and the hardware processor controls distribution of a suction amount in the paper width direction based on stiffness and a paper width, which is a paper size in the paper width direction, of paper.
 2. The paper feeding apparatus according to claim 1, wherein the hardware processor controls distribution of a suction amount in the paper width direction such that a suction amount in a second suction region corresponding to both ends of paper is smaller than a suction amount in a first suction region corresponding to a center of the paper.
 3. The paper feeding apparatus according to claim 2, wherein the hardware processor does not perform suction in the second suction region.
 4. The paper feeding apparatus according to claim 2, further comprising a blower that blows paper, the blower being connected to the suctioning conveyor, wherein the hardware processor suctions paper in the first suction region, and blows paper in the second suction region.
 5. The paper feeding apparatus according to claim 4, wherein the hardware processor starts blowing in the second suction region after uppermost paper is attached onto the suctioning conveyor.
 6. The paper feeding apparatus according to claim 5, further comprising a paper a leading-end blower that blows a paper bundle from a leading-end side of paper in the paper conveyance direction, wherein the hardware processor starts blowing in the second suction region before starting blowing with the leading-end blower.
 7. The paper feeding apparatus according to claim 4, wherein the smaller stiffness paper has, the more the hardware processor decreases a blowing amount in the second suction region.
 8. The paper feeding apparatus according to claim 4, wherein the larger a paper width is, the more the hardware processor decreases a blowing amount in the second suction region.
 9. The paper feeding apparatus according to claim 4, wherein a blowing amount in the second suction region is set such that a blowing amount on a rear-end side of paper is smaller than a blowing amount on a leading-end side of the paper in the paper conveyance direction.
 10. The paper feeding apparatus according to claim 2, wherein the smaller stiffness paper has, the more the hardware processor expands a range of the first suction region to both end sides of the paper.
 11. The paper feeding apparatus according to claim 2, wherein the larger a paper width is, the more the hardware processor expands a range of the first suction region to both end sides of the paper.
 12. The paper feeding apparatus according to claim 1, wherein the suctioning conveyor has a projecting shape such that a distance to uppermost paper on a center of paper is larger than that on both ends of the paper.
 13. A paper feeding apparatus for feeding paper from a paper-mounting table on which a paper bundle is mounted, comprising: a suctioning conveyor that suctions and conveys uppermost paper among the paper bundle mounted on the paper-mounting table; and a hardware processor that controls the suctioning conveyor, wherein the suctioning conveyor includes a suction region for suctioning paper in a paper width direction orthogonal to a paper conveyance direction, and the hardware processor controls distribution of a suction amount in the paper width direction such that a suction amount in a second suction region corresponding to both ends of paper is smaller than a suction amount in a first suction region corresponding to a center of the paper,
 14. An image forming system comprising: a paper feeding apparatus that feeds paper from a paper-mounting table on which a paper bundle is mounted: an image forming apparatus that forms an image on paper fed from the paper feeding apparatus; and a hardware processor that controls the paper feeding apparatus and the image forming apparatus, wherein the paper feeding, apparatus includes a suctioning conveyor that suctions and conveys uppermost paper among the paper bundle mounted on the paper-mounting table, the suctioning conveyor includes a suction region for suctioning paper in a paper width direction orthogonal to a paper conveyance direction, and the hardware processor controls distribution of a suction amount in the paper width direction based on stiffness and a paper width, which is a paper size in the paper width direction, of paper. 